Induction hardening machine



Oct. 24; 1967 M. M. SEELOFF ETAL 3,348,831

7 INDUCTION HARDENING MACHINE Filed June 12. 1964 2. Sheets-Sheet 1 FIG.

INVENTO S MELVIN M. SEELOFF RICHARD K. FOWLER ATTORNEY Oct. 24; 1967 M. M. SEELOFF ETAL 3,343,331

I INDUCTION HARDENING MACHINE Filed June 12, 1964 2 Sheets-Sheet 2 INVENTORS SEE LOF F MELVIN M. BY RICHARD K. FOWLER flaw. K 7

Hill! I l I llllfi ATTORNEY Patented Oct. 24, 1967 3,348,831 INDUCTION HARDENING MACHINE Melvin M. Seelolf and Richard K. Fowler, Warren, Ohio, assignors to The Taylor-Winfield Corporation, Warren, Ohio, a corporation of Ohio Filed June 12, 1964, Ser. No. 374,744 Claims. (Cl. 266-4) This invention relates to automatic equipment for handling, heating, and quenching elongated metal objects such as automotive engine camshafts, and has as its principal object the simplification of such equipment both as to arrangement and manufacture. A further object of the invention is to provide improved equipment of the kind mentioned which by reason of its simplification and the lighter weight of its moving parts will be subjected to less wear and will be capable of continuous operation over large periods with less maintenance. Also, the invention seeks to reduce the cost of manufacturing and setting up equipment of this nature.

Referring now to the drawing, wherein there is illustrated a preferred embodiment of the invention;

FIGURE 1 is a plan view of combined apparatus making up the handling, heating and quenching equipment of the invention, the view showing the quench tank of the assembly in foreshortened condition for economy of space;

FIGURE 2 is a fragmentary right end view of the apparatus of FIGURE 1;

FIGURE 3 is a transverse vertical section through the article handling and quench tank assembly used in the combined structure of FIGURE 1, the view being taken as viewed from the left of FIGURE 1; and

FIGURE 4 is a fragmentary front elevation of the assembly of FIGURE 1.

It has heretofore been common practice to inductively heat elongated metal objects by positioning the same centrally in one or more conductive loops carrying the heating current. The present invention resides, in part, in an improved mechanism for automatically feeding the elongated articles into and out of the heating loops or coils. The apparatus illustrated is intended to heat treat the lobes and bearing surfaces of a camshaft for an automotive engine, and it will be obvious to those skilled in this art that such equipment requires a plurality of current-conductive loops, herein shown at 10, accurately spaced longitudinally to coincide with the longitudinal locations of the lobes and bearing surfaces along the shaft to be treated.

In accordance with usual practice, the opposite ends of the loops are each provided with extensions 11 which are electrically connected to conductive pads 12 supplied with alternating current of suitable frequency from an electrical power unit shown schematically at 13. Mounted on a suitable base 14 forwardly of and slightly below the inductors 10 and in parallel relation with the longitudinal center line of the inductors 10 is an anti-friction track 15. Accurately guided along this track is a first slide 16 which is of appreciable length, as shown, and to which is rigidly attached upwardly and rearwardly extending brackets 17 which rotatably supports a spindle 18. The spindle is arranged to be slowly rotated by a motor reducer 19 driving through a belt 20, and inner end of the spindle is formed with a conical drive head 21 which enters into a conical center detent normally drilled into the end of the camshaft, not shown, which is to be heat treated. Slide 16 is arranged to be actuated by an elongated hydraulic cylinder 22 mounted on the underside of the track 15.

Also accurately guided in the track is a second slide 23 of appreciable length and rigidly carried by the outer end of this slide is a pair of spaced upwardly and rearwardly directed brackets 24. Adjustably but rigidly carried by the brackets 24 is an elongated rod 25 which, as

shown in FIGURE 1, is adapted to be threaded through the inductors 10 and to have its free end portion slideably guided in a bearing 26 rigidly mounted on the base of the machine. Mounted on the free end of the rod 25 is a live center 27 for engaging the conical center recess normally provided in the end of the camshaft, not shown, to be heat treated. The purpose of bearing 26 is to steady the cantilevered end of the rod 25 when the workpieces are rotated within the inductors 10, it being noted that at this time the supporting brackets 24 for the rod are slid far out from the bearing 26. Reference numeral 26' merely denotes a support for a limit switch, not shown herein.

The camshafts or other elongated articles to be treated are loaded, in spanning relation, on a pair of spaced downwardly inclined tracks 28 from which they are deposited, one-a't-a-time, onto a pair of hook-like supports 29. These supports are mounted for downward swinging movement about an axis 30, a hydraulic cylinder 31 being provided for accomplishing this movement.

Slideably mounted for vertical movement below the supports 29 is a pair of spaced supports 32 having V- shaped upper ends 33. The supports 32 are suitably and rigidly connected to move in unison and are arranged to be raised and lowered by a chain 34 which is connected to the slide mounting the supports at 35. As shown diagrammatically in FIGURE 3, the chain 34 is entrained over various sprockets to provide a connected vertical reach for the actuation of the supports 32 or the slide carrying the same and also a horizontal reach which is adjustably connected at 36 to the rod of a horizontally mounted hydraulic cylinder 37. The purpose of this arrangement is to facilitate the adjustment of the mechanism so that the V-shaped supports 33 can be precisely positioned at the upper ends of their strokes to temporarily hold the camshaft or other elongated object to be treated on the common center line of the driving head 21 and the live center 27, previously described. At this position the camshafts are still retained by the hooks of supports 29 although being solidly supported on the V-shaped supports 33, these latter supports being offset from the supports 29 to enable this to be done. In the sequence of operations to be hereinafter described, the supports 29 are retracted downwardly to the left, as viewed in FIGURE 3, after the centers 21 and 27 have picked up a camshaft, and at the same time the supports 32, 33 are lowered to permit the centers to move the camshaft into the inductors 10 in a manner which will now be described. Suitable hydraulic circuits, not illustrated herein, are employed along with various limit switches and sequencing circuits, also not shown, to enable the apparatus above described to be operated in the following manner. Also, in accordance with usual practice, the feed mechanism at the lower end of the tracks 28 is provided with a suitable gate, also not shown, to deposit one article at a time on the supports 29.

Hydraulic fluid under pressure is selectively fed to opposite ends of the cylinders 22 and 38, the latter being provided to actuate the slide 23, and in-the return conduits leading from the outer ends of these cylinders back to the reservoir there is inserted an adjustable relief valve so that a predetermined back pressure can be maintained tending to impede the outward movement of either of the slides 16, 23. Also, suitable speed control valves are inserted in the supply conduits leading to the head ends of the cylinders 22, 38.

At the start of a cycle of operation, the cylinder 22 is fully retracted and by means of limit switches the cylinder 38 is stopped at a predetermined point so that the centers 21 and 27 will both be slightly outside the path of travel of a camshaft or other elongated article which is deposited on the supports 29 by the escapement mechanism above mentioned and positioned ,at the bottom end of the tracks 28. The cylinders 22 and 38 are now actuated to bring the centers 21 and 27 into engagementwith the workpiece to thereby support the workpiece between the centers, and immediately thereafter the supports 29 are retracted downwardly and to theleft, asviewed in FIGURE 3, out of the path of travel of the spindle 18 and its support and driving means. The back or head-end pressure in the cylinder 38 is now reduced by connection through the relief valve above mentioned so that the workpiece is transferred into the inductors where it is slowly rotated by energization of the motor 19 acting through the spindle 18 and the driving center 21. During such rotation, the electric power supply 13 is energized at suflicient intensity and for a suflicient length of time to elfect the desired inductive heating of the lobes and perhaps other sections of the camshaft or other workpiece being treated. Immediately upon this being accomplished the activation of the cylinder-s 22 and 38 is reversed to bring the heated workpiece back to its initial loaded position.

While the workpiece is being brought back to its initial loaded position after beingheated, the V-shaped supports 33 are rising due to activation of cylinder 37, and the timing is such that while the supports 33 do not interfere with longitudinal movement of the workpiece they very quickly move into workpiece-supporting position after the workpiece reaches its initial loaded position. At this time, the cylinders 22 tract the centers 21 and 27 allowing the supports 33 to lower the workpiece into a quench tank 38'. and onto a conveyor 39 housed in the quench tank. This conveyor, not a part of the present invention, may be of any suitable construction but, of course, it must have separated supporting rails to receive the workpiece and to permit the vertical movement of the V-shaped supports 33.

It will be obvious that immediately upon the lowering of a heated workpiece by the supports 33 beyond a predetermined elevation the supports 29 may -be swung upwardly by reactivation of cylinder 31 to receive the next succeeding workpiece from the rails 28. Thereupon the above described cycle for the cylinders 22 and 38 may be reinitiated to grasp this next succeeding workpiece and move the same into and out of the induction heating coils or turns.

The mechanical arrangement of the present invention permits of the maximum'utilization of the productive capacity of the induction heating facility since the workpieces may be quickly loaded, moved into and out of the inductors and then unloaded, the absence of any-heavy reciprocating parts contributing to this result. The arrangement also permits, if desired, that the downward movement of the supports 33 and the heated camshaft or other workpiece supported thereon be arrested temporarily to allow a degree of soaking of the workpiece before it is lowered onto the loading rails of the conveyor 39 and plunged into the bath. The workpieces move through the bath at a controlled speed and are automatically ejected therefrom, all in a more or less conventional manner, as will be understood by those familiar with the art.

It should now also be apparent that we have provided a machine which is capable of automatically hardening, by the electric induction process, elongated workpieces and which is of utmost mechanical simplicity and dependability. In this regard the most important aspect of the invention is the employment of the separate and distinct slides (16 and 23) on the track for mounting, respectively, the drive center and the live center for holding and rotating the workpiece, one of the centers being on the free end of an elongated cantilevered support rod whereby the workpiece may be loaded'and unloaded outside of the induction coil or turns and moved into and out of the coils or turns. By providing an actuating cylinder for each of the slides and suitable hydraulic circuitry for the cylinders under the control of suitable sequencing relays and limit switches, it is possible to utilize these slides not only to close the workpiece supporting centers onto and 38 are activated to repressures for maximum life. Also, since the weight of the the equipment reciprocating parts is kept to a minimum and can be operated at high speed, with minimum power, with minimum shock.

It should be understood that the back pressure or force exerted by the cylinder 38 and the forward pressure or force exerted by the cylinder 22 will remain fixedeven after the slides 16 and 23 have reached the ends of their stroke which move the workpiece from loading position into the inductors 10. Thus, the clamping pressure exerted by the centers 21 and 27 on the workpiece remains constant which is of substantial advantage in that it permits the workpiece to freely elongate under the induction heating withoutdanger of bowing the workpiece. This clamping pressure may be rather light-merely enough to hold the workpiece properly on the centers 21, 27, and upon retraction of the workpiece from the inductors 10 need not be increased to any appreciable extent. There is therefore a minimum tendency to bow the workpiece as the applied heat soaks into it during its return travel back to the loading and unloading station.

Another advantage of our invention is thatsince the elevating-supports 32 are operated independently of the supports 29 and of the slides 16 and 23, the soaking time which may be allotted to a heated workpiece before it is immersed in the quench tank 38 is independent of the general indexing and heating time of the assembly; This makes for wide flexibility of processing, as will be readily understood by those familiar with the metal heat treating art.

Having thus described our invention what we claim is:

1. An induction hardening machine for elongatedworkpieces and of the kind having an annular inductor rigidly mounted on a base and having a fixed longitudinal axis along which the elongated workpiece moves into and out of said inductor comprising the combination an elongated track fixed with respect to said base and axis and being parallel with said axis, a pair of separate and independently slidable slides mounted on said track in longitudinally spaced relation, a loading mechanism to position workpieces in succession in alignment with said axis, one of said slides mounting a spindle with a driving center at one end thereof for rotation about said axis, means on said one of said slides to rotate said spindle, an elongated rod rigidly cantilevered on the other of said slides and having a live center on its free end and positioned for longitudinal movement along said axis concentrically within said inductor, and a double-acting hydraulic cylinder for each of said slides to slide them independently along the same axis, and control means for said cylinders to first retract the slides, from each other to space said centers and permitthe loading and unloading thereon of the workpieces, to then close said centers onto the ends of said workpieces, and finally to move said workpieces into and out of said inductor;

2. In apparatus for heat treating elongated metal workpieces having an annular inductor into which the workpieces is adapted to be moved longitudinally along a fixed axis the improvement comprising a track spaced outwardly from but parallel with said axis, two separate and independently slidable slides on said track and each having a double-acting cylinder connected thereto, one of said slides mounting a motor-driven conical driving center or engaging one end of a workpiece, the other of said slides rigidly mounting a cantilevered elongated rod mounted on said axis and adapted to be threaded through said inductor and mounting at its free end a live lathe center said motor driven center being also on said axis, a feed ing device to position said elongated workpieces in succession on said axis between said centers, and control means for actuating said cylinders so that said centers may be closed onto said work after which the outer ends of said cylinders may be differentially pressurized to advance the engaged workpiece longitudinally along said axis into and out of said inductor and to keep the workpiece constantly clamped between said centers.

3. Apparatus according to claim 2 further characterized in that said feeding device comprises a downwardly inclined track having a retractable and upwardly hooked lower section into which said workpieces may be received singly and in succession, said lower section being operative to temporarily support the workpiece on said axis, means to retract said lower section, and a vertically movable support operative to receive a heated workpiece from said centers upon retraction of the centers and to lower said heated workpiece down past the path of movement of said retractable lower section.

4. Apparatus according to claim 3 further including a quench tank below the path of movement of said vertically movable support, a conveyor in said tank for moving the workpieces sideways through said tank in succession, and a downwardly inclined track in the upper portion of said tank to receive the heated workpieces from said vertically movable support and to transfer the same onto said conveyor.

5. In apparatus for heat treating elongated metal workpieces wherein the workpieces are engaged individually and in succession while lying in a position predetermined by lathe centers for longitudinal movement into and out of an annular electrical inductor the improvement comprising a downwardly inclined track for receiving the workpieces, said track having an upwardly hooked bottom section for supporting the successive workpieces in said position and into which said workpieces are adapted to be deposited one-at-a-time, a. vertically movable support for receiving the heated workpieces from said centers, said bottom section being pivotally mounted for downward swinging movement to one side of the path of travel of the heated workpiece when supported on said vertically movable support, and means to so retract said bottom section.

References Cited UNITED STATES PATENTS 2,506,425 5/1950 Journeaux 266-4 2,665,126 1/1954 Roehm 148-155 X 2,794,894 6/ 1957 Tudbuey 266-4 X 2,942,089 6/ 1960 Baker et al.

2,988,966 6/1961 Spencer 269-33 X 3,189,490 6/1965 Scott 148-153 J. SPENCER OVERHOLSER, Primary Examiner. JOHN F. CAMPBELL, Examiner. J. D. HOBART, R. S. ANNEAR, Assistant Examiners. 

1. AN INDUCTION HARDENING MACHINE FOR ELONGATED WORKPIECES AND OF THE KIND HAVING AN ANNULAR INDUCTOR RIGIDLY MOUNTED ON A BASE AND HAVING A FIXED LONGITUDINAL AXIS ALONG WHICH THE ELONGATED WORKPIECE MOVES INTO AND OUT OF SAID INDUCTOR COMPRISING THE COMBINATION AN ELONGATED TRACK FIXED WITH RESPECT TO SAID BASE AND AXIS AND BEING PARALLEL WITH SAID AXIS, A PAIR OF SEPARATE AND INDEPENDENTLY SLIDABLY SLIDES MOUNTED ON SAID TRACK IN LONGITUDINALLY SPACED RELATION, A LOADING MECHANISM TO POSITION WORKPIECES IN SUCCESSION IN ALIGNMENT WITH SAID AXIS, ONE OF SAID SLIDES MOUNTING A SPINDLE WITH A DRIVING CENTER AT ONE END THEREOF FOR ROTATION ABOUT SAID AXIS, MEANS ON SAID ONE OF SAID SLIDES TO ROTATE SAID SPINDLE, AN ELONGATED ROD RIGIDLY CANTILEVERED ON THE OTHER OF SAID SLIDES AND HAVING A LIVE CENTER ON ITS FREE END AND POSITIONED FOR LONGITUDINAL MOVEMENT ALONG SAID AXIS CONCENTRICALLY WITHIN SAID INDUCTOR, AND A DOUBLE-ACTING HYDRAULIC CYLINDER FOR EACH OF SAID SLIDES TO SLIDE THEM INDEPENDENTLY ALONG THE SAME AXIS, AND CONTROL MEANS FOR SAID CYLINDERS TO FIRST RETRACT THE SLIDES FROM EACH OTHER TO SPACE SAID CENTERS AND PERMIT THE LOADING AND UNLOADING THEREON OF THE WORKPIECES, TO THEN CLOSE SAID CENTERS ONTO THE ENDS OF SAID WORKPIECES, AND FINALLY TO MOVE SAID WORKPIECES INTO AND OUT OF SAID INDUCTOR. 